Kidney Function Impairment Linked to Brain Disorders

Neuroscience News

3 years ago

A growing body of research suggests a link between kidney impairment and brain disorders.

Impaired kidney function may lead to decreased blood flow to the brain, and ultimately to the occurrence of stroke or dementia. The findings, which come from a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN), suggest that maintaining optimal kidney health can provide benefits to the brain.

Stroke and dementia are more common in patients with chronic kidney disease than in individuals in the general population, but it’s unclear why. To investigate a potential kidney-brain link, M. Arfan Ikram, MD, PhD, Sanaz Sedaghat, MSc (Erasmus University Medical Center, in the Netherlands), and their colleagues examined information on 2645 participants in the population–based Rotterdam Study, looking at individuals’ kidney function and blood flow to the brain.

The investigators found that poor kidney function was strongly related to decreased blood flow to the brain, or hypoperfusion. Also, poor kidney function was linked to stroke and dementia most strongly in participants with hypoperfusion. These findings were independent from known cardiovascular risk factors.

The investigators found that poor kidney function was strongly related to decreased blood flow to the brain, or hypoperfusion. This image is for illustrative purposes only. Image credit: Henry Gray.

“Our findings provide a possible explanation linking kidney disease to brain disease,” said Dr. Ikram. “Also, given that kidney disease and hypoperfusion of the brain are both possibly reversible, there might be an opportunity to explore how improving these conditions can ultimately reduce one’s risk of developing brain disease.” The study also shows that the kidney-brain link is not confined to patients with chronic kidney disease, but extends to persons from the general population without overt disease.

CKD is linked with various brain disorders. Whereas brain integrity is dependent on cerebral perfusion, the association between kidney function and cerebral blood flow has yet to be determined. This study was performed in the framework of the population–based Rotterdam Study and included 2645 participants with mean age of 56.6 years (45% men). We used eGFR and albumin-to-creatinine ratio to assess kidney function and performed phase–contrast magnetic resonance imaging of basilar and carotid arteries to measure cerebral blood flow. Participants had an average (SD) eGFR of 86.3 (13.4) ml/min per 1.73 m2 and a median (interquartile range) albumin-to-creatinine ratio of 3.4 (2.2–6.1) mg/g. In age- and sex-adjusted models, a higher albumin-to-creatinine ratio was associated with lower cerebral blood flow level (difference in cerebral blood flow [milliliters per minute per 100 ml] per doubling of the albumin-to-creatinine ratio, −0.31; 95% confidence interval, −0.58 to −0.03). The association was not present after adjustment for cardiovascular risk factors (P=0.10). Each 1 SD lower eGFR was associated with 0.42 ml/min per 100 ml lower cerebral blood flow (95% confidence interval, 0.01 to 0.83) adjusted for cardiovascular risk factors. Thus, in this population-based study, we observed that lower eGFR is independently associated with lower cerebral blood flow.